Water infiltration into homes, high rise condominiums or apartments, and businesses, and even extending to systems in sea craft and cruise liners can amount to serious damage thus causing huge amounts of monetary expense effecting as once this equipment gets wet, particularly in the case of salt water and gas fired equipment, there is no option to repair only replace.
FEMA suggest many ideas to mitigate this risk, including raising equipment to higher floors, hanging equipment off of rafters to raise them up above flood plains, and building an interior floodwall as detailed on their website. The first two instances are options if willing to relocate or installing new equipment but involve significant cost in relocating the piping associated with the equipment. The third, building a flood wall, is also costly and makes many assumptions including that there is a watertight floor, and foundation walls, or significant effort has to be expended to get them to that condition. Moreover, there needs to be a balance between building walls high enough for a recommend 100 year flood, and being able to get over them to service and maintain the equipment or add more cost with waterproof gates or steps.
The source of water can also emanate from the equipment itself, mainly but not limited to hot water heaters, boilers, freezers washing machines, ice makers . . . , and can pose a threat to the homes and business from within. The most common water-leak problem comes from hot water-tank systems, which if left to leak water can and usually does cause serious damage to the basement belongings.
A high rise building such as condos or apartments, serious water-leak damage is most pronounced and more severe than in most homes.